Humming noise from pool heather

[frisky]

Hi: I have a Raypack swimming pool heather 2 years old, working well. Lately has been making a humming noise. Please advise how to take care of it.
Frisky

 

[Bama Rambler]

Re: Humming noise from pool heater

I really hope you mean pool heater!

Is it making a humming noise all the time or just when it's heating?

What is the model of the heater?
Is it gas or electric?

 

[frisky]

May be my reply did not go through.
Sorry, I meant pool heater.
It is a gas heater and makes the humming noise only when is is heating.
Model: Rheem P-407A-EN-X
Thanks

 

[Bama Rambler]

Have you cleaned the burners lately?
It could also be the transformer if it has one.